The present invention relates to suspended ceiling grid systems in general, and to such systems which are fabricated from non-metallic materials in particular.
In many business office spaces and industrial facilities, electrical, plumbing, and ventilation services are carried overhead, and are concealed by underlying ceilings formed of uniform tiles. The tiles are supported by a framework or grid which is carried on wire hangers which are secured to the overhead supports of the building structure. Such hung or suspended ceilings offer the advantage that temporary openings can be readily formed at any desired location for ready access to wires, pipes, or ducts.
Often the supported gridwork is formed of metal shaped into inverted T-shaped members, which have lower flanges which support the ceiling tiles. These metal systems may have cross members with interlocking ends which pass through slots in the perpendicular main runners to engage with other cross members on the opposite side of the main runners. An alternative to metal grid members is provided by fiber reinforced plastic members, formed by pultrusion, which offer a desirable resistance to corrosion, perform better in humid conditions, are electrically nonconductive, and may offer economical construction. Some prior art systems have employed resilient plastic clips which connect the inverted T-shaped pultruded members. These clips press down from above on the central webs of the grid members, and hence intrude into the space which would be occupied by the tiles. Such systems thus either require non-standard tile dimensions (i.e., other than the conventional nominal 2×2 foot or 2×4 tiles), or else result in grid spacings that are non-standard.
What is a needed is a plastic suspended ceiling grid system which accepts conventionally sized tiles in a conventional spacing arrangement.